Generally, a pixel sensor comprises a light source and a photo-sensing panel. The light source is configured to emit a light beam. The photo-sensing panel is arranged to be on a transmitting path of the light beam. The photo-sensing panel comprises a substrate and a plurality of photo-sensing units arranged on the substrate in an array. Each of the photo-sensing units comprises a photo-sensing structure and a readout element (for example, a readout TFT) electrically connected to the photo-sensing structure.
The pixel sensor has a variety of applications. For example, in case of a fingerprint scan, when a user's finger touches the pixel sensor, peaks and valleys of the fingerprint reflect the light beam at different intensities, such that the plurality of photo-sensing structures corresponding to the peaks and valleys respectively receive the reflected light beam at different intensities. Thereby, the pixel sensor can obtain a fingerprint image of the user. In the prior art, a photo-sensing layer of the photo-sensing structure is mostly silicon rich oxide. However, the photo-sensitive spectrum of silicon rich oxide mainly lies in the visible region. In other words, the conventional pixel sensor can only sense visible light and thus is limited in scope of application.